(a) Field of the Invention
The present invention relates to a variable compression ratio apparatus. More particularly, the present invention relates to a variable compression ratio apparatus that changes the compression ratio of an air-fuel mixture in a combustion chamber according to a driving state of an engine.
(b) Description of the Related Art
Generally, a variable compression ratio apparatus changes the compression ratio of an air-fuel mixture according to a driving state of an engine. Such a variable compression ratio apparatus includes a pin link connecting a crankshaft with a piston, a control link changing a trace of the pin link, and an eccentric camshaft changing position of a rotational axis of the control link. Traces of the pin link and the connecting rod are changed by changing position of the rotational axis of the control link and as a result, the volume of the combustion chamber and the compression ratio of the air-fuel mixture are changed.
According to a conventional variable compression ratio apparatus, the control link is disposed vertically under the crankshaft or is disposed horizontally next to the crankshaft. Therefore, the volume of the crankcase may increase.
In addition, since the combustion force is directly transmitted to the connecting rod, the pin link, and the control link, materials may need to be changed or the size of respective components may need to be increased so as to increase the durability of respective components. Therefore, manufacturing costs may increase.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.